Memory Decoding With Reliability Values for Second-Level Parity
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Solution Overview
Problem
Conventional memory systems fail to optimally decode codewords due to suboptimal use of reliability values for second level parity data and user data, leading to incorrect decoding results and failure to correct errors, especially when parity data is stored separately with different reliability characteristics.
Innovation Solution
Selecting different reliability values for second level parity data and user data, with the second level parity data having higher reliability than the first level parity data, and freezing the second level parity data when successfully decoded to improve decoding accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the same reliability values are used for second level parity data and user data, then the decoding process is simpler, but the decoding accuracy decreases and error correction capability is reduced
Solution Approach 1:
The patent applies local quality by assigning different reliability values to different types of data (second level parity data versus user data) based on their specific characteristics and error probabilities. This allows each data type to be decoded with the appropriate level of reliability, improving overall decoding accuracy without uniformly increasing complexity across all data processing.
Solution Approach 2:
The patent segments the decoding process into multiple stages: first decoding second level parity data with higher reliability values, then using those decoded parity values to assist in decoding user data. This segmentation allows the system to handle different data types with appropriate reliability levels, improving error correction capability while managing complexity through structured processing steps.
2Reliability
If second level parity data is not frozen after successful decoding, then more decoding attempts can be made, but the likelihood of incorrect decoding results increases
Solution Approach 1:
The patent applies preliminary action by freezing the second level parity data immediately after successful decoding. This preliminary freezing action prevents subsequent decoding iterations from potentially corrupting the correctly decoded parity values, thereby maintaining high reliability and preventing wasted computational effort on re-decoding already correct data.
3Reliability
If separate storage locations are used for first level parity data and second level parity data, then error correction capability is enhanced, but the system complexity and memory requirements increase
Solution Approach 1:
The patent segments parity data into two distinct levels stored in separate memory locations: first level parity data and second level parity data. This segmentation enables the system to apply different reliability values and decoding strategies to each level, enhancing error correction capability by protecting against different types and severities of errors while maintaining organized memory structure.
Data Source
AI summary
Methods, systems, and apparatuses include detecting a failure to decode a first codeword, the first codeword including user data and first level parity data for the user data. A second codeword is read in response to the detected failure, the second codeword including second level parity data for the user data. A first set of one or more reliability values is selected for the second level parity data, the first set of reliability values differing from a second set of reliability values for the user data and the first level parity data. The user data is decoded using the first level parity data, the second level parity data, the selected first set of reliability values, and the second set of reliability values.